Lubricant for transporting containers on a conveyor system

Abstract

The passage of a container along a conveyor is lubricated by applying to the container or conveyor a mixture of a water-miscible silicone material and a water-miscible lubricant. The mixture can be applied in relatively low amounts and with relatively low or no water content, to provide thin, substantially non-dripping lubricating films. In contrast to dilute aqueous lubricants, the lubricants of the invention provide drier lubrication of the conveyors and containers, a cleaner conveyor line and reduced lubricant usage, thereby reducing waste, cleanup and disposal problems.

We claim:  
     
       1. A concentrate comprising a mixture of (i) at least about 0.8 wt. % of a water-miscible silicone material and (ii) a water-miscible lubricant comprising a polyalkylene-glycol or hydroxyl-containing derivative of a polyalkylene glycol, the concentrate providing a conveyor and container lubricant when diluted with water. 
     
     
       2. A concentrate according to  claim 1  essentially of the water-miscible silicone material and water-miscible lubricant. 
     
     
       3. A concentrate according to  claim 1  consisting of the water-miscible silicone material, water-miscible lubricant and water. 
     
     
       4. A concentrate according to  claim 1  comprising about 0.8 to about 4 wt. % of the water-miscible silicone material. 
     
     
       5. A concentrate according to  claim 1  wherein the water-miscible silicone material comprises a silicone emulsion. 
     
     
       6. A concentrate according to  claim 5  that is sufficiently free of surfactants so as not to cause an increase in stress cracking in a PET Stress Crack Test compared to a concentrate made without such surfactants aside from those that may be required to emulsify the silicone material sufficiently to form the silicone emulsion. 
     
     
       7. A concentrate according to  claim 1  wherein the water-miscible lubricant comprises a polyalkylene glycol. 
     
     
       8. A concentrate according to  claim 7  wherein the water-miscible lubricant comprises a derivative of a polyalkylene glycol. 
     
     
       9. A concentrate according to  claim 8  wherein the water-miscible lubricant comprises a partial ester of a polyalkylene glycol. 
     
     
       10. A concentrate according to  claim 8  wherein the water-miscible lubricant comprises an ethoxylate of a polyalkylene glycol. 
     
     
       11. A concentrate according to  claim 1  further comprising an antimicrobial agent. 
     
     
       12. A concentrate according to  claim 1  having a total alkalinity equivalent to less than about 100 ppm CaCO 3 . 
     
     
       13. A concentrate according to  claim 1  having a total alkalinity equivalent to less than about 30 ppm CaCO 3 . 
     
     
       14. A conveyor and container lubricant composition comprising a mixture of water and a concentrate according to  claim 1 . 
     
     
       15. A composition according to  claim 14  wherein the amounts of the water-miscible silicone material and the water-miscible lubricant are at use levels that (i) reduce the coefficient of friction between a polyacetal thermoplastic conveyor belt and blow-molded polyethylene terephthalate containers to less than about 0.14 and (ii) facilitate movement of such containers along a container filling line. 
     
     
       16. A composition according to  claim 14  having a coefficient of friction less than about 0.14 when evaluated using a Short Track Conveyor Test. 
     
     
       17. A composition according to  claim 14  having a coefficient of friction between about 0.058 and about 0.126 when evaluated using a Short Track Conveyor Test. 
     
     
       18. A composition according to  claim 14  having a coefficient of friction less than about 0.1 when evaluated using a Short Track Conveyor Test. 
     
     
       19. A water-miscible concentrate comprising a mixture of (i) at least about 0.5 wt. % polydimethylsiloxane and (ii) a polyalkylene glycol or hydroxyl-containing derivative of a polyalkylene glycol, the concentrate providing a conveyor and container lubricant when diluted with water. 
     
     
       20. A concentrate according to  claim 19  consisting essentially of the polydimethylsiloxane and the polyalkylene glycol or derivative. 
     
     
       21. A concentrate according to  claim 19  consisting of the polydimethylsiloxane, the polyalkylene glycol or derivative, one or more surfactants that emulsify the polydimethylsiloxane, and water. 
     
     
       22. A concentrate according to  claim 19  comprising about 0.5 to about 8 wt % polydimethylsiloxane. 
     
     
       23. A concentrate according to  claim 19  comprising at least about 0.8 wt. % polydimethylsiloxane. 
     
     
       24. A concentrate according to  claim 19  comprising about 0.8 to about 4 wt. % polydimethylsiloxane. 
     
     
       25. A concentrate according to  claim 19  that is sufficiently free of surfactants so as not to cause an increase in stress cracking in a PET Stress Crack Test compared to a concentrate made without such surfactants aside from those that may be required to emulsify the polydimethylsiloxane sufficiently to form a silicone emulsion. 
     
     
       26. A concentrate according to  claim 19  wherein the water-miscible lubricant comprises a polyalkylene glycol. 
     
     
       27. A concentrate according to  claim 26  wherein the water-miscible lubricant comprises a derivative of a polyalkylene glycol. 
     
     
       28. A concentrate according to  claim 27  wherein the water-miscible lubricant comprises a partial ester of a polyalkylene glycol. 
     
     
       29. A concentrate according to  claim 27  wherein the water-miscible lubricant comprises an ethoxylate of a polyalkylene glycol. 
     
     
       30. A concentrate according to  claim 19  further comprising an antimicrobial agent. 
     
     
       31. A concentrate according to  claim 19  having a total alkalinity equivalent to less than about 100 ppm CaCO 3 . 
     
     
       32. A concentrate according to  claim 19  having a total alkalinity equivalent to less than about 30 ppm CaCO 3 . 
     
     
       33. A conveyor and container lubricant composition comprising a mixture of water and a concentrate according to  claim 19 . 
     
     
       34. A composition according to  claim 33  wherein the amounts of the polydimethylsiloxane and the polyalkylene glycol or derivative are at use levels that (i) reduce the coefficient of friction between a polyacetal thermoplastic conveyor belt and blow-molded polyethylene terephthalate containers to less than about 0.14 and (ii) facilitate movement of such containers along a container filling line. 
     
     
       35. A composition according to  claim 33  having a coefficient of friction less than about 0.14 when evaluated using a Short Track Conveyor Test. 
     
     
       36. A composition according to  claim 33  having a coefficient of friction between about 0.058 and about 0.126 when evaluated using a Short Track Conveyor Test. 
     
     
       37. A composition according to  claim 33  having a coefficient of friction less than about 0.1 when evaluated using a Short Track Conveyor Test. 
     
     
       38. A conveyor and container lubricant composition comprising a mixture of water and a concentrate suitable for dilution with water, wherein the concentrate consists essentially of a mixture of (i) at least about 0.8 wt. % of a water-miscible silicone material and (ii) a water-miscible lubricant comprising a polyalkylene glycol or hydroxyl-containing derivative of a polyalkylene glycol and the composition has a coefficient of friction between about 0.058 and about 0.126 when evaluated using a Short Track Conveyor Test. 
     
     
       39. A conveyor and container lubricant composition comprising a mixture of water and a concentrate suitable for dilution with water, wherein the concentrate consists essentially of a mixture of (i) at least about 0.5 wt. % of a polydimethylsiloxane and (ii) a water-miscible lubricant comprising a polyalkylene glycol or hydroxyl-containing derivative of a polyalkylene glycol and the composition has a coefficient of friction between about 0.058 and about 0.126 when evaluated using a Short Truck Conveyor Test.